1. Field of the Invention
The present invention relates in general to watercrafts, and in particular to the adaptation of a small watercraft with an engine that includes a fuel delivery and injection system.
2. Description of Related Art
Personal watercrafts have become popular in recent years. This type of watercraft is sporting in nature; it turns swiftly, is easily maneuverable, and accelerates quickly. Personal watercraft today commonly carry one rider and one or two passengers.
A relatively small hull of the personal watercraft defines an engine compartment below a rider""s area. An internal combustion engine frequently lies within the engine compartment in front of a tunnel formed on the underside of the watercraft hull. The internal combustion engine commonly powers a jet propulsion device located within the tunnel. An impeller shaft commonly extends between the engine and the propulsion device for this purpose.
Personal watercrafts often employ an in-line, multi-cylinder, crankcase compression, two-cycle engine. The engine conventionally lies within the engine compartment with the in-line cylinders aligned along a longitudinal axis of the watercraft hull (in the bow to stern direction).
A dedicated carburetor usually supplies fuel to each cylinder of the engine. Because of the sporting nature of the watercraft and the tendency for frequent, abrupt directional changes of the watercraft when used, prior personal watercraft engine employ floatless-type carburetors. A fuel system used with the floatless-type carburetors continuously supplies fuel from a fuel tank to the carburetors while returning excess fuel to the fuel tank.
Though floatless carburetors improve fuel delivery to the engine""s intake, prior fuel supply systems have not been so immune to abrupt directional changes. The fuel pick-up port in the fuel tank often is exposed to air when the watercraft leans in a turn, especially when the fuel level within the tank is low. Air in the fuel line produces a number of adverse affects. The fuel/air ratio of the charge delivered to the engine cylinders is reduced which results in poor engine performance. Air in the fuel line also can destroy the fuel pump""s prime, as well as cause some fuel pumps to run hotter and damage the pump either immediately or over time (i.e., reduce the pump""s durability).
Carburetored engines also tend to produce a fuel charge of a less than accurate fuel/air ratio. Consequently, engine performance is not optimized under all running conditions and greater pollutants can result.
The present watercraft includes a fuel injection engine in order to improve the accuracy of the fuel/air ratio of charge delivered to the engine cylinders, as well as reduce pollutants. The adaptation of a fuel injected engine into the small watercraft raises some formidable changes, however, such as, for example, eliminating air intake in the fuel supply system, as well as reducing the heat exposure of the fuel supply and injection system.
Thus, in accordance with one aspect of the present invention, there is provided a small watercraft having a hull defining a rider""s area The rider""s area is positioned behind a bow of the hull and is sized to accommodate at least one rider. An internal combustion engine is located within the hull and drives a propulsion device that is carried by the hull. A fuel supply system includes a fuel tank that communicates with a fuel supply loop extending between the tank and the engine. A fuel pump is positioned within the fuel supply loop to circulate fuel through the supply loop and is located within the fuel tank.
Another aspect of the present invention involves a small watercraft having a hull defining a rider""s area. The rider""s area is positioned behind a bow of the hull and is sized to accommodate at least one rider. An internal combustion engine is located within the hull and drives a propulsion device carried by the hull. An exhaust pipe is connected to the engine. A fuel supply system includes a fuel delivery line and a fuel return line that together define a fuel loop between the engine and a fuel tank. The fuel delivery line communicates with a plurality of fuel injectors of the engine. The fuel delivery and return lines are arranged within the hull of the watercraft such that not more than one of the lines extends next to any portion of the exhaust pipe.
In accordance with an additional aspect of the present invention, a small watercraft has a hull defining a rider""s area. The rider""s area is located behind a bow of the hull and is sized to accommodate at least one rider. The hull has a longitudinal axis and defines an engine compartment. A fuel-injected, internal combustion, multi-cylinder engine is located within the hull engine compartment and drives a propulsion device carried by the hull. The engine has a plurality of fuel injectors to cyclically product a fuel charge within each cylinder of the engine. And a plurality of spark plugs of the engine ignite the fuel charge within the engine cylinders. An electronic control unit communicates with the fuel injectors to control injection timing and volume. The electronic control unit also operates at least one ignition coil, which is connected to at least one of the spark plugs, to control spark timing of the engine. In order to reduce interference noise, the electronic control unit is mounted to the hull at a remote location relative to the ignition coil.